Trouble flashing recovery ROMs

I'm trying to flash Philz-Touch 6.43.4 with either Rashr or Flashify. After it tries to reboot into recovery, the phone stalls on the Motorola DualCore flash screen, then it reboots after about 3-5 minutes to normal boot. This is telling me that the flashing is not working. Does anyone have any instructions on how to flash a recovery ROM?

And before anyone asks, yes, I backed up my stock recovery using Rashr. I've flashed it back a few times, and it always works.

EDIT: So, apparently if I try to load the .img file from the stock recovery, the recovery will not even see the .img file. Maybe it has to be a .zip file, and that's why I'm not getting a proper flash? If so, I guess I won't be using Philz-Touch, as XDA only gives the files in .img form. Of course, if anyone knows how to use ADB and Fastboot, I'm open to suggestion.

EDIT 2: OK, so I figured out the Fastboot thing, kinda. Now it's telling me "<bootloader> Variable not supported" and "FAILED (remote failure)". Stock recovery is still on, so I know nothing was irreversibly damaged. Some other places on Google have mentioned that I need to use a Motorola-specific fastboot.exe file. Does anyone know whether that's true, and where can I find one?